On August 26-27, 2022, the scientific and technological achievements evaluation meeting of "compensation theory and key technology of double-gradient grouting for large deformation tunnel excavation in complex fault fracture zone" was held in Honghe Prefecture, Yunnan Province, China. The project was completed by the State Key Laboratory for Geomechanics and Deep Underground Engineering, Power China Road and Bridge Group Co Ltd, Power China Prefecture Jiangeyuan Expressway Co Ltd, and Power China Sinohydro Bureau 10 Co Ltd. The Chinese Society of Rock Mechanics and Engineering organized the evaluation meeting and held in Mengzi City, Honghe Prefecture, Yunnan Province, using a combination of offline and online modes.
The director of this Evaluation Committee is Xiating Feng (Academician of Chinese Academy of Engineering). The list of members of the Evaluation Committee is as follows: Fuming Wang (Academician of Chinese Academy of Engineering), Xinqiang Niu (Academician of Chinese Academy of Engineering), Zongliang Zhang (Academician of Chinese Academy of Engineering), Fawu Wang (President of the International Consortium on Geo-disaster Reduction (ICGdR), Foreign Fellow of the Engineering Academy of Japan), Jinxiu Yan (President, International Tunnelling and Underground Space Association), Shuyong Yang (Chairman, China National Coal Machinery lndustry Association), Yong Zhao (General Manager, Tibet Railway Construction Company), Zailiang Xu (Survey Master, China Railway Design Corporation), Haibo Zhang (Survey Master, China Railway Eryuan Engineering Group Co., Ltd.), Shengxiang Lei (Chief Engineer, China Railway Construction Corporation Limited), Kairong Hong (Chief Engineer, China Railway Tunnel Group Co., Ltd.), Huajin Wu (Chief Engineer, Department of Transport of Yunnan Province), Jianguo Hu (Chief Engineer, China Railway 12th Bureau Group Co., Ltd.), Wanping Wang (President, CCCC First Highway Consultants Co., Ltd.), Dingjun Qu (Chairman, Hubei Yihua Group Mining Co., Ltd.), Zhihou Li (Deputy General Manager, Yunnan Institute of Transportation Planning and Design Co., Ltd.), Shigui Du (Professor, Ningbo University), Yangzong Zhou (Deputy General Manager, China South-to-North Water Diversion Corporation Jianghan Water Network Construction and Development Co., Ltd.), Guofeng Li (Deputy Chief Engineer, YCIC Highway Construction Co., Ltd.), Dongmei Zhang (Director, Institute of Tunnel and Underground Engineering, Tongji University), Yanjie Zhang (Deputy Director, Collaborative Innovation Center, Yunnan Yunnan Water Diversion Project Construction Administration Bureau). About 170 people participated in the evaluation meeting, they were from Power China Honghe Prefecture Jiangeyuan Expressway Co., Ltd., China Power Kunming Engineering Corporation Limited, JSTI Group, Power China Sinohydro Bureau 10 Co., Ltd., Yunnan Transportation Consulting Co., Ltd., Power China Sinohydro Bureau 8 Co., Ltd., Yunnan Institute of Water and Hydropower Engineering Investigation, Design and Research, China Railway NO.2 Engineering Group Co., Ltd., China Railway NO.10 Engineering Group Co., Ltd., China Railway 12th Bureau Group Co., Ltd., China Railway 16th Bureau Group Co., Ltd, China Railway 18th Bureau Group Co., Ltd, Power China Sinohydro Bureau 14 Co., Ltd., Yunnan Yunnan Water Diversion Project Construction Administration Bureau.
The evaluation meeting was chaired by Professor Jun Yang (Executive Deputy Secretary-General of the Chinese Society of Rock Mechanics and Engineering). The welcome speech was delivered by Lingyun Liang (Deputy Governor of Honghe Prefecture, Yunnan Province). Jieli Li (deputy general manager and chief engineer of Power China Road and Bridge Group Co., Ltd.) introduced the basic situation of the project. Manchao He (Vice President of the International Consortium on Geo-disaster Reduction (ICGdR), Secretary of the Party Committee and Chairman of the Chinese Society of Rock Mechanics and Engineering (CSRME), and Academician of the Chinese Academy of Sciences) attended the meeting and delivered a speech. Other leaders who attended the meeting were: Jiangbo Cui, secretary of the Yunnan Honghe Prefecture Party Committee; Rui Dai, director of the Honghe Prefecture Transportation Bureau of Yunnan Province; and Guihong Bai, chief engineer.
Zhigang Tao (Professor of China University of Mining and Technology (Beijing), Secretary General of the International Correlation Research Program (ICRP)) presented the results on behalf of the project team. The project was completed in cooperation with the China University of Mining and Technology (Beijing), Power China Road and Bridge Group Co., Ltd., Power China Honghe Prefecture Jiangeyuan Expressway Co., Ltd., and Power China Sinohydro Bureau 10 Co., Ltd. The Jianshui (Gejiu) - Yuanyang Expressway is an essential strategic transportation link for the integration of Honghe Prefecture into the regional development, except for the Tabaiyi Tunnel, which has been fully completed. In response to the five major engineering challenges of a complex fault zone, water-rich local fault zone, small clear distance double line interfering, severe weathering of rocks, and strong tectonic stress, based on the excavation compensation theory and double-gradient grouting technology proposed by academician Manchao He, the excavation compensation theory of complex fault zone and double-gradient grouting technology were systematically studied through theoretical analysis, numerical calculation, model test, and field test. The research results reveal the active control mechanism of high stresses in NPR anchor cables in fault fracture zone tunnels and propose the design parameters and methods for double gradient grouting, high-stress NPR anchor networks, and coupled truss control in fault fracture zone tunnels. And the tunnel surrounding rock deformation convergence law is revealed through multi-source monitoring. This project is the first use of double gradient grouting technology, high-stress NPR anchor network, and coupled truss support system, which has improved the construction progress by 56.5%, and achieved a reduction of arch replacement rate from 46% to "0" and second lining and back arch disposal section from 18.7% to "0 " of the breakthrough. It has achieved significant safety, social and economic benefits and has landmark significance to the construction of fracture zone tunnels, with a broad prospect of promotion and application.
The experts of the Evaluation Committee inspected the site of the Tabaiyi Tunnel Project of the Jianshui (Gejiu) - Yuanyang Expressway in Honghe Prefecture, Yunnan Province, listened to the report of the project team, and reviewed the relevant information. After questioning, discussion and evaluation, the Evaluation Committee concluded that the project's overall scientific and technological achievements reached the international advanced level.
On behalf of the project team, Jieli Li, Deputy General Manager and Chief Engineer of Power China Road and Bridge Group Co Ltd, expressed his heartfelt gratitude to the Chinese Society of Rock Mechanics and Engineering for its careful organization and the attentive guidance of the experts present and said that he would further improve the scientific and technological achievements according to the comments of the Evaluation Committee and actively declare the Science and Technology Award of the Chinese Society of Rock Mechanics and Engineering.
